Magnetic Angular Position Sensors Product & Applications Brochure phase detection SPINAXISTM A REVOLUTION IN ANGLE SENSING Quality Assurance & Reliability Commitment The MPS Quality Assurance organization develops, coordinates, and champions strategic, quality initiatives throughout MPS Inc., its foundries, and sub-contractors. Its mission is to enable MPS to design, develop, manufacture, and deliver products to our customers with world-class quality and reliability that meet and exceed our customers’ expectations. MPS and Its Supplier Quality Systems and Certificates: • ISO9001:2008 (MPS) • EU RoHS/HF/REACH Compliant (MPS) • Sony Green Partner (MPS & Suppliers) • TS16949 (Suppliers) • ISO14001 (Suppliers) Product Quality: • Automotive Products Qualified per AEC-Q100 Standard • Standard Products Qualified per JEDEC and Military Standard • Reliability Failure Rate <10FIT • Product Quality Level <1.0ppm Quality Control and Monitor: • On-Site Foundry and Assembly Teams for Real-Time Actions • Quarterly Supplier Quality Review and Annual Supplier Audit • Short-Term Reliability Monitor Test – Daily • Long-Term Reliability Monitor Test – Monthly • Real-Time Engineering Actions on Monitor Failure • Quarterly Reliability Monitor Reports Magnetic Angular Position Sensor Solutions 2016 Magnetic Angular Position Sensor Solutions I N T H I S G U I D E MagAlpha Sensor Overview 4-5 Advantages of MagAlpha Sensors Rotary Human-Machine-Interface Applications 6-10 MA8xx Family MA800: Digital SPI Output MA820: ABZ Output MA850: PWM Output Brushless DC Motor Control Applications 11-20 MA1xx and MA3xx Families MA100: Motor Commutation Sensor MA102: Motor Commutation Sensor Motor Commutation with Position Control (Servo Motor) MA3xx Family MA300: 11 bit Servo Motor Sensor MA302: 12 bit Fast Response Servo Motor Sensor MA310: 12 bit Side Shaft Optimized Servo Motor Sensor MA3xx Applications Servo Motor Example Motor Application Commutation Overview Commutation of Multi-Pole Pair Brushless DC Motors General Angle Sensor Applications 21-26 MA7xx Family Overview MA700: 11 bit General Purpose Angle Sensor MA702: 12 bit Fast Response Angle Sensor MA704: 10 bit Ultra-Fast Response Angle Sensor MA710: 12 bit Side Shaft Optimized Angle Sensor MA730: 14 bit High Resolution Angle Sensor MA750: 12 bit PWM Output Angle Sensor Evaluation Kits 27 Contact 28-29 Simple, Easy SolutionsTM MonolithicPower.com S MonolithicPower.com R O S N MagAlpha Sensor Overview E S The MPS MagAlpha family of magnetic angle MagAlpha sensors use the patented SpinAxisTM Hall N position sensors offers a revolutionary way to measurement technique that provides instantaneous O I measure angles. Leveraging more than a de- angle position in a digital format. SpinAxisTM uses a T I cade of experience, the MagAlpha range offers phase detection approach that eliminates any need S O unique performance advantages compared to for analog to digital conversion or complex angle cal- P rival magnetic sensing technologies. culation used by more traditional technologies (see R Figure 1). A L U G N A C I T E N G A M START STOP B B Phase a Detect t a Figure 1: SpinAxisTM Technique The benefits of the SpinAxisTM technique has allowed MPS to develop different angle sensor ranges span- ning all types of end applications, from low cost consumer rotary knobs to high-speed motor commutation and position control. 4 Magnetic Angular Position Sensor Solutions 2016 M A G N Advantages of MagAlpha Sensors E T Traditional magnetic angle sensors use a set of Hall plates orientated in the X and Y axis that convert I C the amplitude of the rotating magnetic field into a sine and a cosine waveform. The two waveforms are A then digitized with analog to digital convertors (A-to-D), and the angle is computed using an arc tangent N calculation. This approach has several disadvantages. Firstly, the amplitude of the magnetic field being G U measured has to be matched to the A-to-D convertors input range for best results. This limits the mini- L mum and maximum range of the magnetic field that can be accommodated and the magnet’s distance A from the sensor. The second major disadvantage is that the A-to-D conversion and arc tangent calcula- R tion take some time which translates to angle error or position lag at the sensor output. Typical latency P O can be hundreds of microseconds for this older technique. S I T MagAlpha sensors in contrast utilize an array of Hall plates that are sampled successively at very high I O speeds (500kHz or 30 million RPM) in such a way that the signal phase represents the angle to be N measured. The “phase-to-digital” SpinAxisTM technique captures the angle instantaneously every 1μs S without need for A-to-D conversion or arc tangent calculation. This means the sensor is able to work E N over a wider magnetic field range (typically 30-150mT) giving greater flexibility and tolerance for mag- S net positioning. O R The fast Hall sampling and subsequent digital conditioning result in very low latency from Hall array S sampling to the data availability at the sensor output. Typical latency is only 3μs at a constant rotation speed, allowing MagAlpha sensors to operate in systems with high rotation speed or that require fast position control loops. Rotation speeds from zero to in excess of 100kRPM are possible. Side Shaft Capability MagAlpha sensors support both end of shaft and side of shaft topologies. In end of shaft the sensor is placed directly below the magnet connected to the rotating shaft. This topology gives the best per- formance, but is not always mechanically convenient because the end of a rotating shaft may not be accessible. For example, in a motor it may be hidden by the shaft bearing, or driving into a gear box. Side of shaft topology allows the magnet to be placed to the side of a ring magnet mounted on the rotating shaft. This is advantageous for many designs as the ring can be located anywhere on the shaft which allows the sensor to be embedded more easily within the motor or product casing. MagAlpha sensors contain dedicated bias trimming registers which allow the extra magnetic fields seen in side shaft mode to be normalized in amplitude so that the sensor maintains a linear output response over the full angle measurement range (see Figure 6, page 12). MagAlpha Angle Sensors offer the following advantages: • Instantaneous angle sensing: up to 1μs sample rate, only 3μs latency at 100kRPM • High resolution up to 14 bit • Support for shaft rotation speeds from zero to over 100kRPM • Wide magnetic field range support from 15mT to 150mT working range • End and side shaft sensor topologies • Low power consumption: 3.3V, 12mA • Small form factor: 3x3 QFN-16 package Simple, Easy SolutionsTM 5 MonolithicPower.com S MonolithicPower.com R O S Rotary Human-Machine-Interface Applications N E S MA8xx Family N O TI Rotary knobs are used in a diversity of human absolute angular position of a permanent magnet I S to machine interface applications with exam- attached to the rotating knob. Typically, a simple O ples including the program selector on a wash- diametrically magnetized cylinder with a 3 to 8mm P ing machine or the infotainment control in a car. diameter is suitable. R A These applications typically use a conventional L potentiometer or mechanical rotary switch Different options are available, including digital angle U which have limited lifetime due to mechanical output via SPI/SSI bus, incremental ABZ interface, or G N wear and tear or environmental degradation. PWM output. A The use of magnetic angle sensors to im- C plement contactless sensing eliminates both Programmable threshold magnetic field strength de- I T issues to provide a long lifetime solution. tection is built in to enable implementation of a con- E N tactless push or pull button. Detection is performed G The MagAlpha MA8xx family is a new simple- by reading the device registers or the logic state of A M to-use digital magnetic sensor range designed the two output signals. In this way, a combined rotary to replace analog potentiometers or rotary knob with “push or pull to select” functionality can be switches in such applications. The sensor created. detects the VDD MA8xx CS NVM Registers Serial SCLK interface MISO MOSI Spinaxis front-end SSCK Phase Digital SSD detection Conditioning BP PWM PWM (MA850) 2D Hall effect device A ABZ B (MA820) Encoder Z Amplitude MGL detection MGH GND Figure 2: Block Diagram of MA8xx Family Sensor 6 Magnetic Angular Position Sensor Solutions 2016 M A G N E T Push Button Functionality IC A N The MA8xx family provides contactless push or pull button functionality via programmable magnetic field G strength thresholds, which can detect the distance of the magnet to the sensor. The graph in Figure 5 U L shows how this may be implemented with a change in magnet position of approximately 0.9mm crossing A the programmed field threshold to cause the MGH signal to change from logic 0 to logic 1. R P O S I 200 T I 0.6mm O N 180 S button E N 160 pressed S O R 140 S MGH=1 120 threshold 100 1.5mm MGH=0 normal 80 position 60 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Air Gap (mm) Figure 5: Example of Push Button Detection B(mT) v. Air Gap Non-Volatile Memory Configuration parameters are automatically stored in the MA8xx device’s non-volatile memory via the SPI interface. The non-volatile memory provides storage for the reference zero angle position and the magnetic field detection thresholds. The MA8xx family operates from a 3.3V supply and is packaged in a 3x3mm QFN package. The operating temperature is -40 to +125°C. Simple, Easy SolutionsTM 7 MonolithicPower.com S MonolithicPower.com R O S N E S Table 1: MA8xx Family Sensor Range N O I T Features by Part Turning Knob Applications I S O Unit MA800 MA820 MA850 P Digital Out ABZ Incremental Out PWM Out R A Effective angle resolution bit 8 8 8 L U G Magnetic field range mT 30 ..150 30 ..150 30 ..150 N Zero setting A C SPI register configuration I T E Absolute angle on SPI bit 8 N G Absolute angle on SPI bit 8 A M ABZ incremental ABZ resolution PPR 1 .. 64 PWM output PWM resolution bit 8 Magnetic field detection Push button functionality 8 Magnetic Angular Position Sensor Solutions 2016 M A G N MA800: Digital SPI Output E T I C The MA800 sensor outputs the digital angle reading via an SPI or SSI interface. This allows for an easy A interface to all types of microcontrollers. The digital angle is an absolute value with 8 bit resolution between N 0 and 360 mechanical degrees. Because it measures the absolute angle, the position information is always G true, even after the power is cycled. U L A R 3.3 V P O 1 μF N S S I T I MA800 VDD O CS N CLK inteSrPfaIce S E MISO N S O MGH Push Button R MGL interface S MA820: ABZ Output The MA820 version features a programmable incremental ABZ encoder interface. This provides two chan- nels (A and B) of quadrature encoded signals with a programmable number of pulses per channel for each full 360° turn. The pulses per channel can be set from 1 to a maximum of 64 per revolution. The 90° quadrature spacing of the two channels also provides direction of turn information. An index pulse output (Z) is provided to reference the knob’s zero position. The zero reference can be set during system produc- tion and programmed into the non-volatile memory of the device. Figure 3: Quadrature ABZ Waveform 360°/PPT pulses 1 µF N S A MA820 VDD CS SPI CLK interface B MOSI A Encoder Interface B Z 1-64 ppr MGH Push Z Button GND MGL interface 0° 360° Magnetic field angle (deg) Simple, Easy SolutionsTM 9 MonolithicPower.com S MonolithicPower.com R O S N E S MA850: PWM Output N O TI For applications wanting to retrofit to the analogue output of a potentiometer solution, the MA850 version I S provides a PWM output, which can also be filtered to provide a ratiometric linear voltage that is propor- O tional to the angle. The PWM has an 8 bit resolution and frequency of approximately 3.1kHz. Adding an P RC network to the output provides an output voltage over the range from 0 to the device supply voltage of R A 3.3V. For a 0 to 5V application, the RC network can be buffered by a simple OP-AMP circuit to give a wider L output voltage range. U G N 3.3 V A 1 µF C I N S T E MA850 VDD N CS SPI G CLK interface A MOSI M Push PWM MGH PWM Button interface interface MGL GND Figure 4: Example of a Potentiometer-Like Assembly Using Contactless Sensing with MA800/820/850 1 – 2 mm Ø5 mm 3 mm 10 Magnetic Angular Position Sensor Solutions 2016